[FIX] Guard non-dict error items in 404 enrichment (CodeRabbit)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01X8t7DFHq7Dj655kEywKk3K

Author: chandrasekharan-zipstack

backend/middleware/exception.py

@@ -73,7 +73,8 @@ def _enrich_not_found_detail(response: Response | None, context: Any) -> None:
         return
     label = str(model._meta.verbose_name).capitalize()
     for err in data.get("errors", []):
-        if err.get("code") == "not_found":
+        # Guard: a raise here would mask the original error with a 500.
+        if isinstance(err, dict) and err.get("code") == "not_found":
             err["detail"] = f"{label} not found."
 
 

backend/middleware/test_exception.py

@@ -57,3 +57,11 @@ def test_non_404_untouched():
 
 def test_none_response_is_safe():
     _enrich_not_found_detail(None, {})
+
+
+def test_non_dict_error_item_does_not_raise():
+    resp = _Resp(
+        404, {"errors": ["unexpected", {"code": "not_found", "detail": "Not found."}]}
+    )
+    _enrich_not_found_detail(resp, {"view": _View()})
+    assert resp.data["errors"][1]["detail"] == "Lookup definition not found."